(1) Field of the Invention
The present invention relates to an information retrieval apparatus for retrieving and displaying handwritten data, which has been inputted from a handwritten data input unit such as a tablet and is accumulated in a storage unit, according to a designation from a user.
(2) Related Art
In recent years, as information processing apparatuses have been downsized and made increasingly portable, apparatuses for allowing a user to input handwritten data using input devices, such as a combination of a pen and a tablet, have become widely used. These apparatuses adopt various data storing methods. For instance, with one data storing method, handwritten data is inputted in a predetermined character input field, is subjected to a character recognition process, and is stored as a character code. With another data storing method, manuscript handwriting is stored in its inputted form, as the case where a handwritten character is written on paper with a pencil.
With the former method, although retrieval of the inputted data can be performed easily and accurately due to character codes, a user cannot input handwritten data freely and speedily, unlike when using paper and a pencil. This is because the inputted handwritten data needs to be enough accurate for a character recognition process. On the other hand, with the latter method, although a user can input handwritten data speedily, the retrieval of the inputted handwritten data is difficult.
Japanese Laid-Open Patent Application No.7-110845 discloses an information retrieval apparatus that is able to display registered handwritten data in its inputted form. With the apparatus, although handwritten data is stored as it is, handwritten data to be registered and handwritten data used as a retrieval key are both subjected to a character recognition process and are converted into character codes that are used during the retrieval process.
With the apparatus, both the handwritten data to be registered and the handwritten data used as the retrieval key need to be subjected to a character recognition process wherein a plurality of candidate character strings are obtained for the handwritten data and are compared with the handwritten data. This requires considerable processing time, and means that the apparatus needs an extra storage area for storing the obtained potential character strings. Also, since character codes are used for retrieval, handwritten data must be accurate enough for the character recognition process to succeed.